Mobile Launcher redesign plan for SLS nears completion

by Chris Bergin

Teams at the Kennedy Space Center (KSC) are expected to complete a redesign plan for the giant Mobile Launcher (ML) by the end of the month. Re-purposed for the Space Launch System (SLS), companies will soon be able to bid for contracts to carry out the conversion process.

SLS Mobile Launcher:

The ML – designed by RS&H (base and structure), along with ASRC Aerospace Corporation (prop systems etc.) – consists of the main support structure that comprises the base, tower and facility ground support systems, which include power, communications, conditioned air, water for cooling, wash-down, and was designed with ignition over-pressure protection in mind.

Hensel Phelps engineers worked on the structure at the mobile launcher park site area just north of the VAB, with trestles and girders arriving by barge in February of 2009, beginning the opening phase of work to create a base platform – one which is lighter than the current Mobile Launch Platforms (MLPs) that previously hosted the Space Shuttle stack.

ML Under ConstructionWith the giant Launch Umbilical Tower (LUT), the total weight of the structure came in at around 9.5 million pounds, compared to the 8.2 million pounds for just the Shuttle’s MLP.

Fabrication of the 345-foot LUT begin in May of 2009, in preparation for being placed on top of the ML’s platform as the LUT’s base, prior to the addition of nine additional sections via a giant crane at the build site.

The installation of the first section was conducted on September 24, followed by a second section on October 15, a third on October 27, a fourth and fifth section in November, a sixth and seventh in December, followed by the final three sections, resulting all 10 sections being installed by January 28, 2010.

This was followed by the installation of the launch mount – highly specific for only the since-cancelled Ares I vehicle – on the platform in the Spring of 2010.

Ares 1 on ML with Roller Coaster EESHowever, the cancellation of the Constellation Program (CxP) resulted in the ML receiving its pink slip.

Parked up near the VAB, rumors of what would happen to the ML ranged from pulling the structure apart for scrap, through to a joke that was circulated throughout the KSC workforce claiming there was interest from Disney for turning it into a fun ride.

Ironically, Disney engineers had already worked with the KSC team on the roller coaster Emergency Egress System (EES) – a giant structure that is still in the running to be the EES for the SLS.

ML Launch Mount, via L2Although the ML is highly suited to the SLS vehicle, modifications – mainly to the Ares-specific elements of the structure, such as the launch mount – will be required, ahead of the Heavy Lift Launch Vehicle’s debut in 2017.

Such modification planning has been taking place in addition to the umbilical set up required for SLS – a completely different set up to that planned for Ares I.

KSC managers have already sent out a request for information about potential sources for the labor, equipment, and materials to deconstruct and modify the existing Mobile Launcher for SLS – work that will be carried out at the ML Park Site 3 near the Vehicle Assembly Building (VAB).

According to L2 information, the bid package for the reconstruction of the ML was sent to NASA’s legal team for review in late January, with the full details starting to become available to contractors this month via Request For Proposals – the first of which was made available last Friday.

The final details of the redesign were at the 90 percent level in the Design Review as of January, with a completion target date of the end of February. The final elements of the DR relate to the redesigned ML being slightly overweight, with efforts being made to trim excess mass off the ML plan.

SLS and ML at Pad 39B, via L2Some of the final work on the umbilical planning relates to the design of the vehicle stabilizer, with the attach points now located further down the SLS vehicle by around 10 inches. This change was called for in order to make room for a new forward skirt umbilical plate.

This change of placement will result in the attach point structure being located right above the LOX tank dome to the forward skirt interface weld line, with discussions specific to this element of hardware taking place at the Technical Interchange Meeting (TIM) level between SLS’ main contractor, Boeing, and the Marshall Space Flight Center (MSFC).

Meanwhile, modifications to High Bay 3 (HB-3) – where SLS will be stacked atop of the ML – are progressing well.

VAB HB-3 via L2New photos (L2) this past week show all the platforms and gantry walkways – that were once used to surround the Space Shuttle stack during mating and integration – have been removed.

Otherwise known as the “Dog House” platforms, the famous walkways dated back to the Saturn program era. The structures have since been sent for scrap.

The transition of the VAB is aimed at not just hosting SLS, but also commercial vehicles – part of KSC’s “multi-user” facility brief.

Currently, no other vehicle has committed its future to using the building for launch processing, although there remains a possibility a cargo vehicle of ATK’s Liberty rocket may rise to the challenge, while KSC has held notional design meetings relating to the United Launch Alliance (ULA) Atlas V commercial crew rocket becoming a tenant.

(Images: Via NASA and L2 content from L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site.)

(L2 is – as it has been for the past several years – providing full exclusive SLS and Exploration Planning coverage. To join L2, click here:

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